As strange as it might seem, there’s good news in the preliminary finding by Russia’s federal space agency, Roscosmos, that improperly installed instrumentation caused the July 2 crash of the Proton rocket. The human error factor means Proton, one of two main workhorses in the commercial geostationary satellite launch market, presumably can return to flight in relatively short order. 

But the lapse — a stunning example of poor workmanship — cannot be dismissed as an isolated incident given the Proton’s track record of late, particularly on Russian government missions. The rocket has failed four times since late 2010, not counting the December 2012 mission in which its upper stage malfunctioned but the satellite payload ultimately reached the intended orbit using its own fuel. The first in this string of mishaps was caused by an error in fueling the vehicle’s Block DM upper stage, which is built by a different manufacturer than the Breeze M upper stage used on most Proton flights, including all commercial missions. 

In the latest failure, angular-rate sensors on the rocket’s first stage were installed upside-down, and there were indications they were forced into place, according to Roscosmos. With multiple cameras rolling, the rocket, which was carrying three government-owned Glonass navigation satellites, faltered shortly after liftoff, went horizontal and came crashing down in a spectacular explosion that reverberated among commercial satellite operators awaiting Proton launches.

Of the five incidents since 2010, only one, the partial failure, occurred on a mission brokered by International Launch Services (ILS), the U.S.-based company that markets Proton commercially. But ILS customers are nervous, while competitors sense an opportunity: In the wake of the accident, Sea Launch — which suffered a failure of its own Jan. 31 — and Arianespace touted openings on their near-term manifests.

Proton has carried out four successful commercial missions this year and ILS, at least prior to the failure, had hoped to fly two more by September. Among the customers is Inmarsat, which booked Proton flights for all three of its Global Xpress satellites, one this year and two in 2014. 

It remains unclear when Proton will return to flight or whether anxious customers like Inmarsat — the Global Xpress satellites are spearheading the company’s high-stakes foray into Ka-band services — can switch vehicles without incurring longer delays. 

In an interview prior to the failure, Alexander Seliverstov, general director of Proton manufacturer Khrunichev State Research and Production Space Center, said the government-owned company has instituted a quality control program that includes corrective actions for the specific causes of the previous mishaps as well as more-rigorous manufacturing oversight and inspections of key vehicle components. He also said Khrunichev would conduct more-frequent quality audits throughout the Proton production chain and beef up postflight telemetry analysis and employee training programs. 

Mr. Seliverstov’s attention to the Proton’s reliability problem and the steps being taken to resolve it are encouraging, but more needs to be done. Roscosmos said, for example, that Khrunichev did not have in place the monitoring and review procedures that might have flagged the sensor installation errors that doomed the Glonass mission.

Failure investigations by Roscosmos and another Russian-government commission are ongoing. ILS and Khrunichev, meanwhile, say there are insufficient data to link the failure rate on government versus commercial missions to differences in the way the two are managed. 

It nonetheless would appear, based on the initial Roscosmos finding, that at minimum, more-rigorous prelaunch inspections — by senior managers who are held accountable for their work — are required. This might slow Proton’s launch rates a bit, but it’s a small price to pay compared with the alternative.